Higgs Boson |

Site Search Navigation

Search NYTimes.com

Site Navigation

Site Mobile Navigation

Advertisement

Supported by

Higgs Boson

News about Higgs Boson, including commentary and archival articles published in The New York Times. More

The Higgs boson is a cornerstone of modern physics despite never being seen. It is believed to play a key role in imbuing things with mass. It is the last missing part of the Standard Model, a suite of equations that has held sway as the law of the cosmos for the last 35 years.

Physicists have been eager to finish the edifice, rule the Higgs either in or out and then use that information to form deeper theories that could explain, for example, why the universe is made of matter and not antimatter, or what constitutes the dark matter and dark energy that rule the larger universe.

In July, it looked as if the search for the Higgs boson — the longest and most expensive search in the history of science — was coming to an end. Physicists announced that they had discovered a new subatomic particle that looks for all the world like the Higgs boson.

The discovery was announced by physicists at CERN, the multinational research center headquartered in Geneva that is home to the Large Hadron Collider, the immense particle accelerator that produced the new data by colliding protons. But they were cautious about declaring that the particle was the Higgs boson beyond all doubt. It may be an impostor as yet unknown to physics, perhaps the first of many particles yet to be discovered. For now, some physicists are simply calling it a “Higgslike” particle.

Confirmation of the Higgs boson or something very much like it would constitute a rendezvous with destiny for a generation of physicists who have believed in the boson for half a century without ever seeing it. The finding affirms a grand view of a universe described by simple and elegant and symmetrical laws — but one in which everything interesting, like ourselves, results from flaws or breaks in that symmetry.

According to the Standard Model, the Higgs boson is the only manifestation of an invisible force field, a cosmic molasses that permeates space and imbues elementary particles with mass. Particles wading through the field gain heft the way a bill going through Congress attracts riders and amendments, becoming ever more ponderous.

Without the Higgs field, as it is known, or something like it, all elementary forms of matter would zoom around at the speed of light, flowing through our hands like moonlight. There would be neither atoms nor life.

The particle is named for the University of Edinburgh physicist Peter Higgs, one of six physicists — the others are Tom Kibble, Robert Brout, Francois Englert, Gerry Guralnik and Dick Hagen — who in 1964 suggested that a sort of cosmic molasses pervading space is what gives particles their heft. Particles trying to wade through it gather mass the way a bill moving though Congress gains riders and amendments, becoming more and more ponderous. It was Dr. Higgs who pointed out that this cosmic molasses, normally invisible and, of course, odorless, would have its own quantum particle, and so the branding rights went to him.

In 1967, the Nobel Prize-winning physicist Steven Weinberg made the Higgs boson a centerpiece of an effort to unify two of the four forces of nature, electromagnetism and the nuclear “weak” force, and explain why the carriers of electromagnetism — photons — are massless but the carriers of the weak force — the W and Z bosons — are about 100 times as massive as protons.

Unfortunately, the model did not say how heavy the Higgs boson itself — the quantum personification of this field — should be. So physicists have had to search for it the old-fashioned train-wreck way, by smashing subatomic particles together to see what materializes.

In December 2011, two independent teams of scientists, who run giant particle detectors named Atlas and C.M.S. from the CERN collider, reported that they had found promising bumps in their data at masses of 124 billion electron volts and 126 billion electron volts, respectively, those being the units of mass or energy preferred by particle physicists. (By comparison, a proton is about a billion electron volts, and an electron is about half a million.)

Physicists from the Fermi National Accelerator Laboratory in Batavia, Ill., reported that they had found a bump in their data that might be the long-sought Higgs boson. The signal, in data collected over the last several years at Fermilab’s Tevatron accelerator, agreed roughly with results announced in December 2011 from two independent experimental groups working at the Large Hadron Collider at CERN, the European Organization for Nuclear Research, outside Geneva.

None of these results, either singly or collectively, were strong enough for scientists to claim victory. But the recent run of reports encouraged them to think that the elusive particle, which is the key to mass and diversity in the universe, is within sight.

In what amounts to a last hurrah for the Tevatron, physicists said that when they combined the data from some 500 trillion collisions of protons and antiprotons recorded since 2001 there was a suspicious excess, a broad bump in the mass range between 115 billion electron volts and 135 billion electron volts, in the units physicists use to measure mass and energy.

More on the Fermilab Data

In the evidence reported in March 2012, the Fermilab physicists found a broad hump in their data in the same region, between 115 billion and 135 billion electron volts. Those results came from combining the data from two detectors operated on the Tevatron: the Collider Detector at Fermilab, and DZero. The chances of this signal being the result of a random fluctuation in the data were only about 1 in 100, the group said Dmitri Denisov, a leader of the Fermilab effort, wrote in an e-mail: “It is clearly not the answer to crossword, but an important piece of the puzzle!”

Rumors of sightings of the Higgs boson have come and gone at both CERN and Fermilab in the last few years, but invariably where one group saw a bump, another saw a dip in the data, and with more data the bumps went away.

This is the first time in the long search for the particle that different groups, indeed different colliders, are in vague agreement.

It has led to a joke in physics circles now: The Higgs boson has not been discovered yet, but its mass is 125 billion electron volts.

The Atlas and C.M.S. groups will be trying to combine and reconcile their data in the coming weeks. The Hadron collider, now on winter break, will start up again in April 2012, with protons colliding at four trillion electron volts apiece. CERN has said that the collider will gather enough data this year either to confirm the existence of the Higgs boson or to rule it out forever.

Either outcome, physicists say, will be exciting. If the Higgs does not exist, they will have to come up with a new model of how the universe works. If they do find the Higgs, studying it might give them clues to deeper mysteries the Standard Model does not solve.